Question: Simplify the following expression: $k = \dfrac{10ts + 15s}{25rs - 15ts} + \dfrac{25rs}{25rs - 15ts}$ You can assume $r,s,t \neq 0$.
Solution: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{10ts + 15s + 25rs}{25rs - 15ts}$ The numerator and denominator have a common factor of $5s$, so we can simplify $k = \dfrac{2t + 3 + 5r}{5r - 3t}$